f\\1'*t'    '  IS 


U.S.  DEPARTMENT  OF  AGRICULTURE, 

BUR]  Ai    OF  PLANT  IND1  STRY     I  ircular  No.  46. 
B.   r.  ■■  W.U'WAY,  Chief  of  Bureau. 


THE  LIMITATION  OF  THE  SATSUMA  ORANGE 
TO  TRIFOLIATE-ORANGE  STOCK. 


WALTER  T.  SWINGLE, 

Physiologist  in  Charge  <>i-  Crop  Physiology    \m> 
Breeding   I  \\  estigations. 


WASHINGTON  :  GOVERNMENT  PRINTING  OFFICE  :  1600 


r-affi&ii^ 


U.S.  DEPOSITORY 


BUREAU  OF  PLANT  INDUSTRY. 


Chief  of  Bureau,  Beverly  T.  Galloway. 
Assistant  Chief  of  Bureau,  Albert  F.  WOODS. 
Editor,  J.  E.  Rockwell. 
Chief  Clerk,  James  E.  Jones. 


[Cir.  46] 
2 


B.  r.  i 

THE  LIMITATION  OF  Fill-:  SATSUMA  ORANGE  TO 
TRIFOLIATE-ORANGE  STOCK.0 


INTRODUCTION. 

The  Satsuma  orange  is  a  variety  which  has  come  to  be  widely 
grown  in  the  warmer  parts  of  the  Gulf  States.  Without  entering 
into  a  discussion  as  to  the  merits  and  demerits  of  this  variety,  it  is 
proposed  in  this  circular  to  call  attention  to  the  fact  that  unlike  most 
commonly  grown  varieties  it  succeeds  onlj  when  grafted  on  Trifoliate- 
orange  >tock  and  is  a  complete  failure  on  the  sour-orange  stock  upon 
which  almost  all  other  citrus  fruits  can  be  grown  successfully. 

In  view  of  the  fad  thai  large  experimental  and  even  commercial 
plantings  of  the  Satsuma  orange  are  being  made  in  nearly  all  of  the 
Gulf  States  and  that  Satsuma  trees  are  being  offered  for  sale  on  sour- 
orange  stock,  it  is  considered  advisable  to  call  at  tent  ion  to  t  he  certain 
failure  which  will  result  from  planting  Satsuma  oranges  budded  on 
sour  stock.  Fortunately  a  simple  method  has  keen  discovered  for 
identifying  with  certainty  Trifoliate  stock,  which  makes  it  easy  to 
guard  against  the  fradulent  substitution  of  sour-orange  or  any  other 

stock  for  t  he  Trifoliate. 

HISTORY   OF  THE  TRIFOLIATE   ORANGE   IN  THIS  COUNTRY. 

Growers  of  citrus  fruits  in  this  country  have  long  keen  accustomed 
to  use  the  sour  orange  and  the  sweet  orange  as  stocks,  while  in  recent 
years  the  rough  lemon  and  to  a  lesser  extent  the  grapefruit  have  come 
into  use.  These  show  widely  different  adaptation  to  soil  conditions, 
as  well  as  greatly  varying  powers  of  disease  resistance. 

Among  the  stocks  which  have  come  into  prominence  during  the 
past  few  decades  is  the  hardy  Trifoliate  orange  of  China  and  Japan. 

'■  During  the  las!  few  years  then'  have  been  extensive  plantings  of  the  Satsuma 
in  the  warmer  parts  of  the  Gulf  States.     Withoul  entering  into  a  discussion 
his  variety  and  the  prospects  for  growing  and  marketing  ii  suci 
full  -    mmercial  scale,  Mr.  Swingle  call  attention  in  the  present  cir- 

cular to  the  unusually  .-harp  limitations  of  this  variety  to  i  the  Trifoliate 

orange.     It  is  believed  to  be  desirable  to  warn  all  who  desire  to  tesl  the  variety  against 
purchasing  trees  budded  on  the  sour  orange,  a  sb  kably  well  adapted  toaln 

all  other  kinds  of  citrus  fruits,  but  which  Mr.  Swingle  finds  to  fail  entirely  for  this 
particular  variety. 

mple  method  i<>r  distinguishing  the  Trifoli  from  all  other  stocks  in 

points!  out,  rendering  it  easj   to  protect  purchasers  of  Satsuma  oranges  against  the 
titution  of  sour-i  ["rifoliate  stock.— B.  T.  Galloway,  (  eau. 

[Cl«  3 


LIMITATION    OF    SATSUMA    ORANGE. 


Pig    i   -a  fruiting  branch  n r  the  Trifoliate  orange     (Natural  size.) 


1.1  M  !  I  \  HON    OF    SATSU  tfA  ORANi  0 

This  was  introduced  into  this  country  by  the  Department  of  Agri- 
culture in  L  869  and  was  at  first  little  more  th  itanical  curiosity. 
Ii  was  soon  Found  to  be  an  excellent  bedge  plant  in  the  South,  and 
even  as  far  north  as  Washington,  D.  ('..  and  for  many  years  it  was 
grown  for  this  purpose.  The  fact  that  it  is  able  to  withstand  without 
injury  temperatures  as  low  as  zero  Fahrenheit,  or  even  lower,  makes 
it  suitabli   for  culture  ovei  nearly  half  the  area  of  the  United  Mates. 

Those  forms  of  the  Trifoliate  orange  which  have  fully  deveL 
flowers  are  handsome  ornamentals,  especially  when  they  blossom  in 
the  spring  and  again  when  laden  with  fragrant  yellow  fruit  in  the 
autumn.  Unfortunately  many  of  the  Trifoliate  orange  trees  grown 
in  i  lii-  country  do  not  develop  their  flowers  perfectly,  or,  at  least ,  not 
all  of  t  heir  flowers,  t  he  petals  being  stunted  and  shortened  by  gland- 
like growths  on  the  edges  near  the  base.  The  flowers  arc  shown 
natural  size  in  Plate  I.  A  fruiting  branch  is  shown  in  figure  I.  and 
fruits  in  cross  section  and  in  longitudinal  section  in  figures  2  and  '■',. 


hi  of  a  fruit  of  the 
Trifoliate  orange. 
(Natural  size.) 


Fig.   3.— Longitudinal  section  of  a 
fruit  of  the  Trifoli 

(Natural  size.) 


It  would  he  very  easy,  however,  to  breed  up  a  large-flowered  race  of 
the  Trifoliate  orange  that  could  be  propagated  very  rapidly  and 
cheaply  from  t  he  superabundant  seeds  that  (ill  the  fruits. 

The  Trifoliate  orange  has  been  used  for  ages  in  China  and  Japan  as 
a  stock  upon  which  to  hud  the  cultivated  citrus  fruits,  and  about  the 
middle  of  the  last  century  it  was  broughl  to  notice  in  England  as  a 
stock  for  the  kumquat.  This  latter  species  itself  was,  bowever, 
only  a  curiosity,  and  apparently  very  lew  experiments  were  made  in 
Europe  with  the  Trifoliate  orange  as  a  stock  for  oranges,  lemons,  and 
other  common  citrus  fruits. 

About  a  quarter  of  a  cent  ury  ago  t  be  Trifoliate  orange  began  to  he 
used  in  this  country  i  ck  for  the  Satsuma  orange,  as  well  as  for 

other  citrus  fruits.  It  w  as  found  that  all  grow  well  on  this  stock,  and 
that  it  had  a  tendency  to  force  early  and  profuse  bearing,  at  the 
same  time  dwarfing  the  tree  somewhat. 

[Cir.  40] 


6  LIMITATION    OF   SATSUMA  ORANGE. 

Although  the  Trifoliate  is  naturally  a  small  tree  and  of  slow 
growth,  when  used  as  a  stock  its  growth  is  so  stimulated  that  its 
diameter  always  continues  greater  than  that  of  the  scion.  This 
disparity  in  size,  while  not  sufficient  to  make  the  union  a  poor  one, 
makes  it  easy  in  walking  through  a  grove  of  citrus  fruits  budded  on 
this  stock  to  detect  the  point  of  union  of  the  scion  with  the  stock 
because  of  the  abrupt  increase  in  diameter  of  the  latter." 

The  Trifoliate-orange  stock  has  one  disadvantage  in  comparison 
with  sour-orange,  sweet-orange,  and  other  commonly  used  stocks — 
it  does  not  sprout  readily  from  the  root  if  the  top  is  killed  by  a 
severe  frost.  For  this  reason  varieties  grafted  on  Trifoliate  roots  and 
grown  where  there  is  danger  of  occasional  severe  freezes  should  always 
be  earthed  up  a  few  inches  above  the  point  of  insertion  of  the  bud,  so 
that  in  case  the  top  is  killed  by  a  severe  freeze  the  budded  variety  can 
be  reproduced  by  sprouts  issuing  from  that  part  of  the  trunk  which 
is  protected  by  the  earth.  If  this  precaution  is  neglected  there  is 
danger  of  orange  trees  grafted  on  Trifoliate  stock  being  killed  out- 
right, root6  and  branch,  by  an  unusually  severe  winter. 

THE  KUMQUAT  SUCCEEDS  BEST  ON  TRIFOLIATE-ORANGE  STOCK. 

There  are  very  few  varieties  of  citrus  fruits  that  do  not  succeed  on 
the  Trifoliate  stock,  provided,  always,  the  soil  is  adapted  to  the  stock. 
Some  varieties  succeed  better  on  this  stock  than  on  any  other.  Per- 
haps the  most  striking  example  of  this  is  the  kumquat,  which  is  the 
hardiest  of  the  evergreen  citrus  fruits.  On  Trifoliate  stock  it  bears 
heavy  crops  of  fruit  while  still  a  mere  hush. 

On  the  other  hand,  the  kumquat  is  not  adapted  for  budding  on  sour- 
orange  stock,  and  such  buds  often  fail  to  grow,  or  even  die,  alter  they 
have  started  to  push,  something  very  rare  among  citrus  fruits.' 

THE   SATSUMA  ORANGE  A  FAILURE  ON  SOUR-ORANGE   STOCK. 

Another  variety  of  citrus  fruits  that  behaves  very  differently  on 
the  various  stocks  is  the  Satsuma,  a  very  early  orange  of  t  he  mandarin 
class  introduced  from  Japan,  where  it  is  known  as  1  he  Unshiu.  This 
variety,  which  is  the  earliest  and  at  the  same  time  one  of  the  hardiest 

"  Tli is  form  of  union  wherein  the  stock  slightly  outgrows  the  scion  has  been  noticed 
also  in  the  ease  of  the  loquat  grafted  on  the  quince  growing  at  Eustis,  Fla.  In  this 
case,  al  ariety  so  grafted  began  t<>  bear  when  still  very  young  ami  has  borne 

abundant  crops  since.  It  is  interesting  to  nolo  that  in  both  of  these  cases  we  have  a 
;  i  :■  ived  evergreen  plant  grafted  on  a  small  leaved  deciduous  and  □  >i  verj  closely 
related  Bpecies.  The  contrary  union,  where  the  scion  outgrows  decidedlj  the  stock, 
is  apparently  not  satisfactory,  the  scion  being  likelj  to  break  off  and  being  usually 
I  lived,  even  w  I  capes  being  broken  ■ 

''The  Trifoliate  root,  strictly  speaking,  is  not.  killed  outright,  but  as  it  produo 
sprouts  it.  soon  dies  from  starval  ion. 

<  l'i  i  these  facts  the  writer  is  indebted  to  Mr,  < ..  1..  Tabor,  of  Glen  St.  Mary,  Fla 

[Cir.  46] 


. 


Plate 


A  Flowering  Branch  of  the  Trifoliate  Orange,  Showing  the  Flower  Fully 
Expanded  before  the  Leaves  Appear.    iNatural  Size. 


Digitized  by  the  Internet  Archive 
in  2013 


http://archive.org/details/lisatsOOunit 


LIMITATION    01    SATSUMA    OB  INGE.  7 

of  the  oranges,"  grows  \er\  well  on  sweet-orange  stock — better,  in 
fact,  than  on  the  Trifoliate  orange  on  most  soils-  but  the  fruit  is  of 
decidedly  inferior  quality  on  the  former  stock,  being  coarse,  dry,  and 
insipid,  besides  ripening  later  than  on  the  Trifoliate  stock. 

( >n  the  sour  orange  the  Satsuma  is  a  complete  failure,  the  growth 
being  so  slo'w  and  stunted  that  it  never  becomes  more  than  a  dwarfed 
bush.  The  fruit  that  is  borne  by  this  stunted  tup  is  of  very  inferior 
quality.  There  is  every  evidence  of  a  considerable  degree  of  incom- 
patibility between  the  Satsuma  and  the  sour  orange.  It  is  no  exag- 
geration to  say  that  he  who  plants  a  Satsuma  orange  tree  grafted  on 

ir  stock  might  better  bury  a  live-dollar  l>ill  and  burn  the  tree, 
which,  if  planted,  will  linger  along  for  years,  <>nl\  to  be  finally  dug  up 
as  worthless.  Enquiry  among  growers  of  Satsuma  oranges  in  Florida. 
bama,  Mississippi,  Louisiana,  Texas,  and  northern  Mexico  has 
failed  to  elicit  a  single  instance  of  successful  growth  and  satisfactory 
fruiting  of  this  variety  budded  on  sour-orange  stock.  The  writer 
was  stationed  for  five  years  in  Florida  investigating  citrus  fruits  in 
all  part-  of  the  State,  and  during  that  time  he  never  saw  a  vigorous 
Satsuma  tree  or  any  good  crops  of  early-ripening  fine-flavored  Sat- 
suma oranges  borne  on  trees  budded  on  sour-orange  stock. 

THE  SATSUMA  ORANGE  BEST  ADAPTED  TO  TRIFOLIATE-ORANGE 

STOCK. 

On  the  other  hand,  the  Satsuma  budded  on  the  Trifoliate  orange 
produce-  fruits  which  ripen  early  and  are  of  excellent  quality .  smoot  h 
skinned,  linn,  and  juicy.  The  trees  budded  on  this  stock  are  smaller 
than  those  budded  on  sweet-orange  stock,  hut  they  hear  earlier  and 
fruit  more  profusely.  They  also  ripen  their  fruits  earlier  in  the 
season  and  are  decidedly  hardier. 

The  Satsuma  orange  is  the  only  one  of  the  commonly  grown  citrus 
fruits  (besides  the  kumquat)  which  shows  such  marked  differences 
in  growth  and  character  of  fruit  when  budded  on  different  stocks. 
Since  the  Satsuma  orange  can  succeed  on  hut  one  stock,  the  Tri- 
foliate orange,  it  can  he  grown  with  hope  of  commercial  success  only 
"ii  soils  to  which  the  Trifoliate  stock  i-  adapted,  namely,  on  fairly 
riil  hat  moist  soils,  preferably  sandy  soils  with  a  clay  subsoil. 

It  i-  almost  impossible  to  successfully  grow  orange  tree-  budded 
upon  Trifoliate  stock  on  light,  sandy  -oil-  such  as  make  up  the  hulk 
of  the  -oil  of  southern  Florida  and  parts  of  southern  Texas. 

!  ia  autumn,  and,  v  ■  the  lasl  growth  has 

hardened,  the  tree  can  endure  a  consid  ither  without  b< 

.Hi.     This  high  degree  of  winter  dormancy  is  what  renders  i  lie  Satsuma 
r  culture  in  the  variable  <  limah  As  to  the  quality 

Phis  is  dm 
pari  varying  quality,  depending  on  the  stock  upon  which  ii  is  budded 

nd  climat  «  hen-  it  is  grow  a. 


LIMITATION    OF    SATSUMA   OEANGE. 


Iii  case  the  soil  is  not  adapted  to  the  Trifoliate  orange,  there  is 
little  hope  of  growing  the  Satsuma  orange  successfully  unless  some 
new  stock  not  as  yet  known  is  found  adapted  to  this 
variety  and  able  to  grow  on  light  soils.  As  a  last 
resort,  grapefruit,  citrange,0  or  some  other  stock  could 
be  tested,  but  it  is  useless  to  set  out  trees  of  this  variety 
grafted  on  sour-orange  stocks. 

HOW  TO  DISTINGUISH   TRIFOLIATE    FROM  SOUR- 
ORANGE   STOCK. 

In  1887,  Prof.  Otto  Penzig,  director  of  the  botanic 
garden  at  Genoa,  Italy,  published  a  very  interesting 
account  of  citrus  fruits  for  the  Department  of  Agri- 
culture, Industry,  and  Commerce 
of  the  Italian  Government.  In  the 
course  of  his  investigations  of  the 
anatomy  of  the  principal  types 
of  citrus  fruits,  he  discovered  a 
striking  difference  in  the  structure 
of  the  pith  of  the  Trifoliate  orange 
•eiis  that  make     as    compared    with    that    of    other 

up  the  imper-         .  ,,      . .     , 

feet      cross      CltlllS  il'iuts." 

plates.    (Mag-        if  a  section  be  made  lengthwise 


Fig.  4.— Longi- 
tudinal section 
of  the  pith  of 
the  Trifoliate 
orange,  show- 
ing the  thick- 
walled,   pitted 


ni(ied50  diame- 
ters.)   (Drawn 


of  a  stem  or  twig  of  the  Trifoliate 


hy  Dr.  Theo.  orange,  the  pith  is  found  to  con- 
tain rows  of  cells  arranged  so  as  to 
form  more  or  less  imperfect  partitions  some- 
what like  the  partitions  in  the  pith  of  the  wal- 
nut. Such  a  section  of  the  Trifoliate  orange 
showing  the  cross  plates  of  thick-walled  cells 
in  the  pith  is  shown  in  figure  4  to  be  contrasted 
with  figure  5,  showing  the  absence  of  any  such 
plates  in  the  pith  of  the  sour  orange.  A  few  of  the  thick-walled 
cells  winch  make  up  the  imperfect  longitudinal  cross  partitions  of  the 
Trifoliate  orange  are  shown  under  higher  magnification  in  figure  6. 


Fig.  .">. — Longitudinal  sec- 
tion of  the  pith  of  the 
sour  orange.  Note  i  he 
nee  of  any  thick- 
walled  cells.  (Magni- 
fied 56  diameters.) 
(Drawn  by  Dr.  Theo. 
Uolm.) 


a  The  citrange  is  a  hardy  citrus  fruit  originated  by  the  Department  of  Agriculture 
ssing  the  common  orange  and  the  Trifoliate  orange.  Citranges  grow  more  vigor- 
ously than  cither  parent,  and  some  varieties  can  be  reproduced  practicallj  unchanged 
from  the  ihih.it.iuh  seeds.  Becau  e  of  their  vigor  and  their  being  half  orange,  cifc- 
ranges  can  be  expected  to  thrive  in  soils  too  light  for  the  straight  Trifoliate.  As  the 
Satsuma  oi  ■■■  s  rapidly  on  sweet  orange  stock  and  fruits  well  on  Trifoliate 

slock,  ii  would  probably  succeed  on  the  citrange,  a  hybrid  of  these  two  stocks. 

6  Penzig,  0.     Studi  boi  li  agrumi  e  sulle  piante  affine,  in  ^nnali  di  Agricol- 

tura,  L8S7,  p.  L37,  pi.  13,  fig.  6  (Ministero  di  Agricoltura,  Endustria  e  Commercio). 
e,  L887. 
[Cir.  46] 


LIMITATION    0  CJMA    ORANGE. 


9 


Fig.  6.— A  i  thick-walled  cells 

from  the  pith  ofthe  I 
nified 372 diameters.)    I  Drawn  by  l> 
Bolm.) 


A  longitudinal  section  of  the  pith  of  the  sour  orange  is  shown  in 
figure  5.  li  will  be  noted  thai  there  is  an  entire  absence  of  cross 
partitions,  and  there  arc  no  thick  walls  to  be  seen.  All  of  the  ordi- 
nary types  of  citrus  fruits,  including 
the  sour  orange  and  all  that  arc 
ever  used  as  stocks  in  this  country, 
have  pith  of  this  character  without 
any  trace  of  cross  partitions  built  up 
out  of  thick-walled  cells. 

These  peculiar  cells  are  of  such  a 
striking  character  as  to  make  it  easy, 
l>v  using  a  low-power  microscope,  t o 
distinguish  between  Trifoliate  and 
sour  orange  stocks  in  fact,  to  dis- 
tinguish Trifoliate-orange  from  any 
othercitrus  stock  «  ii  h  absolutecer- 
tainty.  To  make  such  an  examina- 
tion it  is  of  course  necessary  to  take 
out  some  of  the  pith  of  the  stock. 
In  the  case  of  nurserj  stock  this 
can  even  be  done,  if  desired,  without  killing  the  plant,  since  a  cut 
extending  half  way  through— necessary  to  take  out  the  pith- will 
soon  heal  up. 

WARNING   AGAINST  THE   PURCHASE   OF   SATSUMA   ORANGES   ON 
SOUR-ORANGE  STOCKS. 

In  >pite  of  the  fact  that  Satsuma  oranges  budded  on  sour-orange 
stock  are  known  to  be  a  total  failure,  some  nurserymen  have  budded 
them  largely  on  this  stock  and  are  even  offering  them  for  sale  on 
round  thai  the  Trifoliate  stock  <\<>vs  nol  succeed  on  light,  sandy 
soil,  whereas  sour-orange  stock  does  succeed  in  such  -it  nations.  All 
tin-  is  perfectly  true,  hut  no  mention  i-  made  of  the  additional  and 
very  important  qualification  that  the  Satsuma  orange  budded  on 
sour-orange  stock  i-  perfectly  worthless  from  a  commercial  point  of 
view   on  au\   soil. 

In  \  iew  of  these  facts,  this  occasion  is  taken  to  urge  intending 
purchasers  of  Satsuma  oranges  to  insist  thai  they  be  budded  on 
Trifoliate-orange  stock.  In  no  case  should  they  be  accepted  mi 
sour-orange  stock.  If  the  experiment  is  to  be  made  of  growing 
S.-ii^'  oranges  in  a    region   where  the  soil   is  light,  especially  in 

south*  i  Florida  and  southern  Texas,  it  may  be  wort h  while  to  experi- 
ment with  the  Satsuma  on  certain  other  stocks,  such  as  grapefruit 
or  seedling  citrange,  but  there  is  little  hope  for  financial  success  in 
growing  Satsuma  oranges  in  such  situations. 

[Cir 


10  LIMITATION   OF   SATSUMA    ORANGE. 

In  order  to  make  it  possible  for  orange  growers  to  be  sure  that 
they  are  getting  plants  grafted  on  Trifoliate-orange  stock,  the  De- 
partment of  Agriculture  will  undertake  temporarily  to  determine, 
free  of  charge,  whether  or  not  nursery  stock  of  citrus  fruits  is  grafted 
on  Trifoliate-orange  stock.  It  is  hoped  that  this  method  will  be 
adopted  by  state  horticultural  inspectors  and  by  stale  experiment 
stations,  as  well  as  by  growers  themselves.  It  is  the  purpose  of  this 
temporary  offer  of  the  Department  to  make  known  the  possibility 
of  distinguishing  readily  whether  or  not  the  stock  used  is  the  Tri- 
foliate orange. 

SUMMARY. 

It  is  not  the  purpose  of  this  circular  to  discuss  the  merits  or  demerits 
of  the  Satsuma  orange  or  to  attempt  to  define  the  regions  in  which 
it  can  be  grown  with  reasonable  hope  of  success. 

The  Satsuma  orange  is  almost  a  complete  failure  on  sour-orange 
stock  on  any  soil  and  in  any  climate,  ami  succeeds  well  only  when 
budded  on  Trifoliate-orange  stock.  It  can  be  grown,  but  less  suc- 
cessfully, on  sweet-orange,  grapefruit,  ami  perhaps  rough-lemon 
stocks. 

The  Satsuma  orange,  being  limited  to  the  Trifoliate-orange  stock, 
can  be  grown  with  reasonable  hope  of  success  only  on  soils  to  which 
this  stock  is  well  adapted,  namely,  fairly  rich,  fairly  heavy  soils, 
preferably  with  a  clay  subsoil. 

Purchasers  of  Satsuma  orange  trees  should  insist  that  they  be 
grafted  on  Trifoliate-orange  stock,  and  to  protect  purchasers  against 
substitution  of  trees  grafted  on  sour-orange  stock  the  Department 
of  Agriculture  will  undertake  for  the  present  to  determine  whether 
or  not  the  stock  is  Trifoliate  orange. 

Do  not  buy  Satsuma  oranges  budded  on  sour-orang<  stock!  If  you 
suspect  substitution,  send  a,  sample  to  the  Department  of  Agriculture 
for  determination. 

Approved : 

James  Wilson. 

Secretary  of  Agriculture. 

Washington.  1).  ('..  December  6,  1909. 

[Cir.  46] 

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